Coin selector utilizing a coin impeller

ABSTRACT

A coin selector which utilizes a coin impeller is disclosed, the impeller comprising .[.magnetic field means.]. .Iadd.a magnetic field generator .Iaddend.for accelerating the coin. Coin velocity sensing .[.means .]. .Iadd.photodetectors .Iaddend. located downstream from the coin impeller and associated circuitry serve to compare the coin&#39;s acceptance ratio with predetermined values for acceptable coins. .Iadd.

This application is a continuation of reissue application Ser. No.423,220, filed Dec. 10, 1973, now abandoned, .Iaddend.and acontinuation-in-part of Patent Application Ser. No. 858,351 filed Sept.16, 1969, now abandoned.

This invention relates to coin selectors which determine theauthenticity and denomination of coins and, more particularly, tomagnetically impelling coins in a coin selector.

Coin operated devices, such as vending machines, coin changers and tollbooths have universal acceptance and are widely used. These coinoperated devices must have the capability of accurately and rapidlydetermining the authenticity and denomination of coins entering thedevice.

The coin impellers of this invention induce a wide velocity rangebetween coins of different denominations making it easier to test andsort coins accurately. By virtue of the fact that the motion given tothe coin through the coin selector system is effected primarily by thecoin impeller rather than by gravity, the velocity variance for anygiven coin is extremely small, in the order of ±2 percent. Reliabilityand effectiveness of the coin selector of this invention is high becauseof the minimal variation in coin velocity.

Accordingly, it is one objective of this invention to provide a coinselector and method of coin selection utilizing a magnetic impeller ofcoins in order to substantially improve the reliability andeffectiveness of a coin selector in sensing the authenticity anddenomination of coins.

Another objective of this invention is to provide a coin selector whichis both unaffected by the velocity imparted to a coin as it is insertedinto the coin selector relatively independent of coin wear.

In the drawings:

FIG. 1 is a schematic, elevational diagram of a device for determiningthe authenticity and denomination of a coin, the device including arotary coin impeller formed in accordance with a first embodiment ofthis invention which utilizes permanent magnets.

FIG. 2 is a schematic plan view of a coin selector including a rotarycoin impeller formed in accordance with a second embodiment of thisinvention which utilizes electromagnets.

FIG. 3 is a schematic illustration of a linear motor coin impellerformed in accordance with a third embodiment of this invention.

FIG. 4 is a schematic elevational diagram of a coin selector utilizingthe linear motor impeller of FIG. 3.

FIG. 5 is a diagram of a circuit enabling the use of D.C. to energize alinear motor impeller while FIG. 5A is a table and FIG. 5B is a logicvoltage time plot showing the operation of the circuit of FIG. 5.

FIG. 6 is a schematic elevational diagram of a coin selector formed inaccordance with a fourth embodiment of this invention.

FIG. 7 is a schematic elevational diagram of a coin selector formed inaccordance with a fifth embodiment of this invention utilizing a pair oflinear motor impellers.

FIG. 8 is a schematic elevational diagram of a modification of the fifthembodiment of FIG. 7.

FIG. 9 is a schematic elevational diagram of a coin selector formed inaccordance with a sixth embodiment of this invention utilizing aplurality of inclined impellers and coin support tracks.

FIG. 10 is a schematic elevational diagram of a coin impeller formed inaccordance with a seventh embodiment of this invention utilizing atapered linear motor impeller.

FIG. 11 is a schematic elevational diagram of a modification of theseventh embodiment of FIG. 10.

DETAILED DESCRIPTION Coin Selector

Throughout this specification and in the appended claims, the term"coin" is intended to mean genuine coins, tokens, counterfeit coins,slugs, washers, and any other item which may be used by persons in anattempt to use coin-operated devices. Furthermore, throughout thisspecification, for simplicity, coin movement is described as rotationalmotion; however, translational motion also is contemplated.

With reference to FIG. 1, there is illustrated, in schematic form, acoin selector 10 for electrically conductive coins comprising, in part,a coin support track 12, coin arrestor means 14, a magnetic coinscavenger 15, a coin impeller 16, a brake magnet 18 and means 20 forsensing functions dependent upon properties of a coin to determine thecoin's authenticity and denomination.

A coin, after entering the coin selector device 10, passes through acoin arrestor means 14. In FIG. 1, the arrestor means comprises ameander path which absorbs most of the coin's kinetic energy and reducesthe coin's velocity in the horizontal direction to an insignificantvalue. Any magnetic coin scavenger 15, such as one of the typesillustrated in U.S. Pat. Nos. 1,956,066 and 3,168,180 is located in thepath of coin travel to extract coins made of ferromagnetic material fromthe coin selector 10. It is desirable to remove such coins whenpermanent magnets are located elsewhere in the system to avoid havingferromagnetic coins trapped by those magnets. Alternatively, one or moreof the other magnets could serve as a magnetic coin scavenger ifadditional means are provided to clear the magnets of a magnetic coinwhich is adhered thereto. As the coin approaches the coin impeller 16,it passes an arrival sensing device 22 which senses the presence of acoin in the system. While many sensing devices are suitable, such asmicroswitches or inductive switches, a preferred sensor is aphotoelectric device such as a photocell operating in combination with alight source, and the coin being directed between the light source andphotocell. The signal from the photocell indicating coin presence,through an amplifier 24, energizes a start control system 26 forpurposes to be described below.

The coin, illustrated by the phantom lines 28, reaches the coin supporttrack 12 where it is brought into proximity with the coin impeller 16.The track 12 forms the bottom of coin passageway 29 and primarily servesas a support for the coin 28. The track 12 is not provided with asufficient slope to cause the coin to roll with significant velocity.While the track can be horizontal, it is preferred that the track have aslight slope, in the order of 2° and not greater than 5°. A slightdownward slope toward the property sensing means 20 is preferred; sothat in the event that an electrically non-conductive coin, such as aplastic disc, is inserted into the coin selector 10 and is unable to bepropelled by the coin impeller 16 the slignt slope of the track 12 willcause the coin to roll through the system at a slow speed. This willprevent the coin from remaining near the impeller 16 and eliminate thechance that the coin will accelerate to a velocity equal to the velocityof an acceptable coin. Alternatively, the track 12 can be orienteddownwardly away from the property sensing means 20 toward a coinrejection chute (not shown).

Rotary Coin Impeller - (FIG. 1)

The coin impeller 16 is formed in accordance with the first embodimentof this invention includes a rotor 30 formed of a non-magnetic materialsuch as plastic which has a plurality of permanent magnets 32 mountedaround the periphery thereof, three such magnets (six pole faces) beingillustrated in FIG. 1. The magnets are mounted so that the polarity ofadjacent magnets alternate between north and south. The rotor 30 ismounted so that the coin 28 is located on one side of a diametrical line33 parallel to the coin support track 12. This is accomplished bykeeping the center of rotation of the rotor 30 below the plane of thesupport track 12. The purpose for this is to ensure that the coin issubjected to a magnetic flux having a horizontal component only in thedirection in which it is desired that the coin travel, namely, from leftto right in FIG. 1 when the rotor rotates clockwise.

An arriving coin passes through the meander path 14 and occludes thephotocell 22 which, through the signal generated by the occlusion of thesensor, signals the start control 26. The start control 26 includes,among other things to be discussed below, switch control means forenergizing the motor to rotate the rotor 30. When the coin arrives atthe impeller 16 the rotating magnets (rotating in the clockwisedirection as illustrated in FIG. 1) produce a rotating magnetic fieldhaving a horizontal component above the coin support track 12 in thedirection toward the property sensing means 20. The rotating magneticfield induces eddy currents in the coin 28 producing an associatedmagnetic field which interacts with the rotating magnetic field toproduce a force on the coin in the direction of movement of thetraveling magnetic field, namely from left to right in FIG. 1. Thecoin's acceleration and ultimate velocity are dependent upon the coin'sacceptance ratio, which is its electrical conductivity divided by itsdensity.

The impeller 16 normally is sufficient to provide enough of a velocitydifferential between coins having different coin acceptance ratios topermit coin discrimination. However, with some coin sets it may bedesirable to supplement the impelled velocity differential by utilizingan eddy magnetic current brake. A stationary permanent magnet 18 islocated on one side of the coin support track 12 and a second magnet orplate (not shown) of ferromagnetic material such as mild steel, islocated directly opposite the magnet 18 in order to provide a constantfield across the coin passageway. As the coin passes through the regionof the stationary magnetic field eddy currents are induced in the coinand the associated magnetic fields, which oppose the field inducing theeddy currents, interact with the stationary magnetic field to create aretarding force. In other words, the resultant force on the coin is inthe direction from right to left in FIG. 1. The magnitude of the coin'sdeceleration is dependent upon the coin's acceptance ratio, as well asthe velocity of entry of the coin into the stationary magnetic field andthe area of the coin and the magnetic field region.

Coin Acceptance Ratio Sensor

The coin leaving the stationary magnetic field supplied by the permanentmagnet 18 enters the region of sensing means 20 which together with acombinational circuit are provided to examine the property of the coinrelated to velocity. A particular apparatus used is described in detailbelow with reference to FIG. 4. The sensing means together with thecombinational circuit provide a signal to a solenoid controlled inclinedplatform 36 indicative of the acceptability of the coin. If, the coin isunacceptable it rolls off the track 12 and is directed into a rejectionchute 34 by the platform 36. If the coin is determined to be acceptablea solenoid (not shown) is actuated and retracts the platform 36 from thepath of the coin allowing the coin to fall into an acceptance chute 38.

Electromagnetic System (FIG. 2)

The first embodiment described above employs permanent magnets 32 aspart of the impeller 16 and a permanent magnet 18 as the magnetic brake.Alternatively, electromagnets can be used either for the impeller or forthe magnetic brake or for both.

An electromagnetic coin impeller 50 is illustrated in FIG. 2 andincludes a non-magnetic rotor 52 on which are mounted a plurality ofC-shaped iron cores 54 (only one of which is illustrated). The cores aremounted on the rotor 52 so that only the pole faces 56, 58 extendthrough and face the coin support track 12. A wire coil 60 is woundabout the central portion of the iron core 54, one end of the coin beingconnected to a slip ring 62 mounted on a shaft 64 leading from the rotor52 to a driving motor 66. The other end of the coil 60 is electricallyconnected to a second slip ring. Electricity from a source 70, shown asalternating current (A.C.) but which could be direct current (D.C.), isconveyed to the coil 60 through the slip ring 62 and shaft 64 in anyconventional manner, such as by shoes 72, 74. If A.C. is used, the rateof rotation of the rotor 52 and the frequency of the current should bechosen to avoid minimum magnetic field strength when the magnet is abovethe track 12 such as might be caused if the relationship of frequencyand rotation is such that one or more of the electromagnet poles issubject to an A.C. zero crossing while the pole is above the track 12. Alow reluctance magnetic shunt such as a plate 75 of ferromagneticmaterial is mounted opposite the upper half of the rotor 52 to affect aconstant field across the coin passageway so that a coin's movement isinfluenced relatively uniformly regardless of which side of the trackthe coin is on.

If a magnetic brake is used, any conventional electromagnet can beutilized as the brake magnet 76. A D.C. electromagnet is preferredbecause the transit time of a coin through the field generated by thebrake magnet 76 is comparable to or less than the frequency period ofconventional current, namely 60 cycles. If A.C. current is used, thebraking experienced by a coin is dependent upon the timing of its entryinto the magnetic field relative to the phase of the current supply. Toavoid this problem and to establish satisfactorily high levels ofbraking, a substantial current is passed through the electromagnet coilresulting in the generation of, and the need to dissipate a substantialamount of heat. Because of these problems, a D.C. electromagnet ispreferred. A ferromagnetic plate 77 is mounted opposite to the brakemagnet 76 to provide a constant magnetic braking field across the coinpassageway.

It will be recalled that as the coin 28 enters the system and approachesthe coin impeller, it passes an arrival sensor 22 which senses thepresence of the coin and actuates a start control 26. The start control,through switch means, actuates the coin impeller 50 and the eddy currentbrake electromagnet 76 for a prescribed time interval which is longenough to permit the slowest acceptable coin to pass through the system,after which the switches are opened inactivating the coin impeller 50and electromagnet 76.

Since this system utilizes electromagnets which can be renderedsubstantially neutral by cutting off the current supply, there is noneed to use a ferromagnetic coin scavenger. If a coin of ferromagneticmaterial is inserted into the system, it will be trapped by one of theelectromagnets, probably the impeller magnet. After the current throughthe magnets is terminated, the ferromagnetic coin will roll slowly downthe coin support track 12 under the influence of gravity. The ultimatedeparture velocity of the ferromagnetic coin will be extremely low dueto the slight slope of the track 12 and due to the residual magnetism ofthe electromagnets, thereby permitting distinction between ferromagneticcoins and other coins which have a low velocity. Instead of relyingmerely on the track slope and the residual magnetic field to ensure avery low velocity for ferromagnetic coins, a third magnet 78 having avery low flux density can be utilized downstream from the brake magnet76.

It is also important, in order to produce consistent and reliableresults, for the magnitude of the current switched into theelectromagnets to be controlled within limits, preferably less than ±1/2percent. This can be accomplished by conventional rectifying, filteringand regulating circuitry not illustrated or described herein but whichis well known in the art.

Linear Motor Impeller (FIGS. 3 & 4)

In place of the rotary coin impeller described above in connection withthe first and second embodiments, it is preferred to use stationarymeans for producing a traveling magnetic field. Such can be accomplishedby using a linear motor which is similar to a stator of a conventionalcylindrical electric motor which has been cut along a radial plane andunrolled out flat. As is illustrated in FIG. 3, such an impeller 80comprises two series of coils, a first series including coils 82 and 84and a second series including coils 86 and 88. While only two coils perseries are illustrated, a greater number of coils is preferred, forexample, about four per series. The coils are wound around a low carbonsteel impeller core 90 having projecting pole pieces or core fingers92-95 spaced longitudinally along the desired direction of coin travel.A low reluctance magnetic shunt or magnetic return path 98 is placed atthe side of the coin track 99 opposite the impeller 80 to provide auniform magnetic field across the coin passageway. The magnetic shuntmay be made of a low carbon steel plate. It is desirable in the case ofhigh flux densities that the core 90 be laminated steel.

In order to produce the effect of a traveling magnetic field, it isnecessary for adjacent fields to have a phase shift relationship. FIG. 3illustrates a circuit which is suitable for providing approximately a90° phase shift between adjacent core fingers. It can be seen that thefirst series of coils 82, 84 is wound in alternating fashion, in otherwords, coil 82 is wound in a counterclockwise direction about corefinger 92 while coil 84 is wound clockwise about core finger 94. Thesecond series of coils 86, 88 similarly is wound in alternating fashion,namely coil 86 is wound counterclockwise about core finger 93 while coil88 is wound clockwise about core finger 95.

Either the first series or the second series of coils can beindividually selectively connected directly to a source of cyclicallyvarying current, for example, chopped D.C. or single phase sinusoidalA.C. current source 100, such as by AND gate 102 and AND gate 104respectively, which are controlled by signals from start control circuit106. In the case where single phase sinusoidal AC current is used, thetwo series are connected in parallel through a capacitor 108 thusplacing the capacitor in series with the coil series not directly gatedon. The capacitor 108 provides a 90° phase shift between the two seriesof coils. Because of the reversed direction of windings of adjacentcoils within a series and the phase shift between the coil seriesprovided by the capacitor 108, the magnetic field is effectivelytraveling in one direction. For example, at one instant of time assumingthe polarity of the first coil 82 is north, the polarity of coil 86 isnorth plus 90°, the polarity of coil 84 is south and the polarity ofcoil 88 is south plus 90°. The thrust direction of impeller 80 isreversed by merely enabling the presently disabled AND gate and viceversa. This permits selection of a desired thrust direction for purposesdescribed below.

To provide consistent coin velocities, it is preferable to activate theimpeller 80 each time at the same fixed point in the impeller currentwave form. In this way the resultant coin velocity is not dependent uponthe particular moment of time when the coin is first exposed to themagnetic field of the impeller. The zero crossing detector 109 isdesigned to detect the zero crossing of the impeller current in thedirection providing desired initial polarity. The zero crossing detector109 includes a saturation amplifier, a diode and differentiator toselect the desired direction of transition and a latching relay operatedby the output of the differentiator.

Coin Selector System

Turning now to FIG. 4, a coin selector system 110 for nonferromagneticcoins, utilizing a linear motor impeller 80, is schematicallyillustrated. A coin entering the system through an entrance slot 112drops vertically downward through an entrance meander section 114 whichslows the coin and removes most of its energy. The coin passes anarrival sensor 116 such as a photocell which senses the presence of thecoin in the system and, through an amplifier 118, energizes a startcontrol system 120 which in turn energizes the impeller 80 after aslight delay. After passing the arrival sensor 116 the coin drops onto acoin support track 122.

The support track is designated with an initial short section 124 havingan inclined slope of between 0.5° - 5.0°, preferably approximately 1.5°,followed by a declining longer portion having a declination ofapproximately the same slope. The coin drops onto the initial portion124 and, due to the inclination, rolls rearwardly (toward the left inFIG. 4) until it comes to rest against a wall 128. The system isdesigned with a delay in energizing the impeller such that the impelleris energized after sufficient time has elapsed for the coin to come torest against the wall 128. The impeller is located with respect to thetrack 122 such that portions of at least two pole faces are adjacent theresting place of the smallest coin desired to be accepted by the coinselector. Once the impeller is energized, the coin, if electricallyconductive and para or dia-magnetic, will be caused to move along thetrack 122 by rolling up the inclining portion 124 and then down thedeclining portion 126. The coin movement is produced by eddy currentsinduced in the coin which produces an associated magnetic field. Theinteraction between the induced magnetic field in the coin and the fieldof the forwardly adjacent coil of the impeller causes the coin to movetoward that coil. The acceleration and velocity of the coin as it leavesthe impeller 80 is determined by the coin's acceptance ratio for thereasons discussed above. The impeller is turned off by a signal from thesensors indicating that the coin has left the impeller.

If a ferromagnetic coin is inserted into this system, it will beattracted to the impeller and retained in place. After a predeterminedperiod of time, which is based upon the longest period of time thatwould be required for an acceptable coin to traverse the support track122, the impeller is turned off and the ferromagnetic coin remains atthe initial section 124 of the track. By operation of any conventionalcoin rejection system the ferromagnetic coin is forced to drop off thetrack 122, into a coin rejection receptacle. Similarly, if anelectrically nonconductive coin, such as a plastic slug, is insertedinto the system, the coin will not be impelled by the impeller 80 andwill be removed by the coin rejection system.

In order to insure proper impelling of nonferromagnetic electricallyconductive coins, of the impeller poles are spaced so that anyacceptable coin will be influenced by the fields of two polessimultaneously, so that the coin feels the effect of the travelingmagnetic field. This may be accomplished by designing the impeller sothat the dimension between corresponding points of adjacent pole piecesis no greater than the diameter of the smallest acceptable coin. Toavoid a high loss factor and heating, the spacing between adjacent polesof the impeller should be more than the effective air gap between theimpeller 80 and the magnetic shunt 98. The effective air gap between theimpeller 80 and the magnetic shunt actually is twice the distancebetween the impeller and the shunt because the effective gap is basedupon the entire magnetic path and, therefore, includes the gap twice,once at the north pole and once at the south pole. It can be seen thatin constructing the impeller, the two design parameters just discusseddefine the lower and higher limits for the spacing between adjacentcoils. If a compromise is needed in order to satisfy these designparameters, the loss factor and heating caused by distance between thepoles being less than the air gap can be tolerated within limits.

As described above, the coin support track 122 is provided with aninitial inclined portion 124 for the purpose of bringing the incomingcoin to rest at a predetermined position. One alternative to this designis to utilize a track having a continuous surface declining from thewall 128 at an angle of approximately 11/2°. When the coin enters thesystem and passes the arrival sensor 116, the impeller is initiallyenergized to impel the coin in a rearward direction or, in other words,toward the wall 128. After a short period of time with the impellingforce continually being exerted on the coin toward the wall 128 the coinwill be brought to rest against the wall at which time the direction ofthe magnetic field is reversed and the coin is impelled forwardly awayfrom the wall 128. This insures that all coins start from rest and froma fixed position and provides the desired consistency of performance.

Electronic Coin Acceptance Ratio Sensing System

The impeller 80 causes the coins to move along the track 122 with avelocity which is dependent upon the coin's acceptance ratio. It now isnecessary to determine if the coin is acceptable. This is accomplishedby coin presence sensors and associated combinatorial circuitrydescribed hereinafter or, for example, by those devices disclosed incopending applications assigned to the assignees of this application:Ser. No. 91,871, filed Nov. 23, 1970, Ser. No. 172,922 filed Aug. 16,1971, and Ser. No. 219,327, filed Jan. 20, 1972.

For purposes of the discussion below it is assumed that the coinselector 110 is designed to accept coins of only one denomination,although it is clear that the coin selector is capable of distinguishingseveral different coins by employing the disclosed techniques.

The coin, being impelled by the impeller 80 toward the right in FIG. 4passes a pair of conventional sensors or detectors such as inductiveswitches, photoelectric devices, etc. In this discussion, photocells areused as sensors. Light sources (not shown) and photocells 132, 133 aremounted on opposite sides of the track 122, the photocells being locatedclose together and in close proximity to the impeller 80. As the coinleaves the impeller 80 it occludes the first sensor 132 which sets aflip flop 136 enabling an AND gate 138. When the coin occludes sensor133, the flip flop 136 is reset, disabling the AND gate 138. Theinterval during which the flip flop 136 is set is inversely proportionalto the coin velocity and, therefore, is inversely related to the coin'sacceptance ratio.

The output pulses of timing oscillator 140 are fed to the enabled ANDgate 138 from which they are gated into a counter 144. The output of thecounter, which is fed to a decoding matrix 146, is inverselyproportional to the velocity of the coin. The output of the decoder 146is fed to flip flop 150. A flip flop is set by the count representativeof the lower limit of acceptable velocity for the particular coindenomination which the flip flop represents and is reset by the countrepresentative of the upper limit of velocity of that particular coin.If a coin having a velocity within the range of an acceptable coinpasses through the system, flip flop 150 will be set indicating that acoin which has passed through the system has a velocity within a rangeequal to the velocity range that an acceptable coin would have afteracceleration by the impeller.

An accurate examination of a coin's velocity may not be sufficient toaccurately determine the authenticity and denomination of a coin. It hasbeen found that the information obtained from conducting both anexamination of a chordal dimension of the coin and an examination of itsvelocity provides sufficient information to confidently determine thecoin's authenticity and denomination.

One method of determining whether a coin's diameter or other chosenchordal dimension is within an acceptable range is illustrated in FIG.4. A pair of sensors 132, 135 corresponding to each acceptable coin isemployed in combination with a primary sensor 133, the sensor 135 closerto the primary sensor checking the minimum acceptable dimension and thesensor 132 further from the primary sensor checking the maximumacceptable dimension. The distance between the pair of sensors 132, 135is equal to the acceptable dimensional variation of a particular coinand the distance between the sensor 135 and the primary sensor 133 isequal to the minimum acceptable dimension for that coin. The invertedoutput from the sensor 132 and the output from the sensor 135 are fed toseparate inputs of an AND gate 139. The primary sensor 133 is connectedthrough a capacitor 143 to the input of an inverting gate 147. A sourceof power sufficient to operate gate 147, in this case 5 volts, is alsoconnected to the same input through a resistor 145. The output of gate147 is connected to an input of AND gates 139. When the primary sensor133 is first obscured, capacitor 143, resistor 145 and the voltageapplied through resistor 145 produce a short pulse at the input of ANDgate 139. If a coin passing through the coin selector 110 has aparticular dimension larger than the distance between the primary sensor133 and the nearest sensor 135 but smaller than the distance between theprimary sensor 133 and the furthest sensor 132, and flip flop 150 is setwhen sensor 133 is first occluded, then AND gate 139 is enabled when thecoin first occludes sensor 133 and a flip flop 141 is set indicatingthat a coin of acceptable dimension and velocity has passed through theselector.

Since each pair of sensors 132, 135, each AND gate 139 and each flipflop 141 represents one coin, the number of these elements used equalsthe number of denominations of coins the coin selector 110 is designedto accept. Also, each acceptable coin has a corresponding coin velocityflip flop (for example flip flop 150) and the output from this flip flopcan be fed to the AND gate 139 for that coin so that when the flip flop141 is set it indicates that both the chordal dimension and coinacceptance ratio dependent velocity of the coin passing through the coinselector 110 is the same as those properties of a particular acceptablecoin.

Impeller Current Control of Clock Oscillator Frequency

The acceleration of the coin is proportional to the current through theimpeller coils. The coil current is dependent on the magnitude of theexciting or source voltage and the impedance of the impeller windings.Conventional A.C. supply voltage varies by at least ±10 percent and theresistance of the windings changes by a similar amount due totemperature, manufacturing variances and minor variations in wirediameter. Because the coin velocity is dependent upon the strength ofthe impeller's magnetic field, and the magnetic field strength isdependent upon the voltage supply, supply voltage variations cause aresultant change in coin velocity and, therefore, a change in theelapsed time during which coins of the same denomination pass betweenthe two sensors 132, 133. If the clock oscillator 140 which feeds pulsesinto the counter 144 has a constant frequency regardless of the impellercoil current, the number of clock pulses gated into the velocity counter144 will vary with changes in impeller current for identical coins andcould indicate unacceptability of a coin which actually is acceptable.

To overcome this problem a feedback signal derived from the impellercurrent source 100 is applied to the clock oscillator 140 by the circuit152. The impeller 80, including the coils and phase shift capacitor,receives its current from the supply 100 and a current sampling resistor154 is placed in series with the impeller 80. The clock oscillator 140is a voltage controlled oscillator and the control voltage is suppliedby means of a transformer coupling 156 the primary of which is acrossthe current sampling resistor 154. The oscillator current is caused tobe of the proper polarity by circuit 152 so that as the impeller currentincreases thus increasing the coin velocity and reducing the timeinterval during which the clock pulses are gated into the counter 144,the oscillator frequently is increased. The higher oscillator frequencyprovides a greater number of pulses to the counter 144 to compensate forthe shorter gate time. Conversely, when the impeller current decreasesand the coin velocity decreases, the oscillator frequency is decreasedto gate fewer pulses into the counter during the longer gate time.Therefore, while the coin's actual velocity varies considerably becauseof supply voltage variations, the apparent velocity is normalized towithin 1 percent or 2 percent by this system.

Switched Direct Current Energization of Impeller (FIG. 5)

Instead of using power line frequency A.C. to energize the impeller 80,in some instances, it is advantageous to use switched D.C. The circuitillustrated is FIG. 5 is one technique which can be utilized. There isillustrated two dual clocked R--S flip flops 160, 162 whose operation isdescribed by means of the table shown in FIG. 5A and the logic voltagediagram 5B. The dual flip flops are interconnected in a manner which, atthe frequencies involved (e.g.: under 4,000 Hz) eliminates thepossibility of ambiguity associated with simultaneous similar logicstates at the "S" (set) and "R' (reset) inputs of each dual flip flop.The dual clocked R--S flip flops 160, 162 do not change state until apositive input pulse is received. Flip flop 160 is readied to changestate by a coin entering the system such as by means of the startcontrol system 120. When the first positive clock input pulse isreceived transition takes place (t₁) and the change of state of Q₁ andQ₁ readies flip flop 162 for a change of state, which change occurs atthe next positive clock pulse (t₂). When Q₂ and Q₂ change state flipflop 161 is readied for a change of state which occurs at the nextsuccessive positive clock (t₃) and so on.

The outputs of the flip flops 160, 162, which have a quadrature phaseshift relationship, are used to drive pairs of full-wave switches 164,165 and 166, 167 respectively to enable alternate excitation ofcenter-tapped windings 168, 169 of a two phase impeller by a D.C. source170. This produces a quadrature phase shift in the impeller windings168, 169 effecting a traveling magnetic field.

The D.C. resistance of the impeller windings changes with changingwinding temperature which, therefore, effects the magnetic fluxmagnitude. Compensation for these changes can be made by regulating theimpeller supply voltage. This is accomplished by placing temperaturesensitive elements, such as nickel wire resistor 172, 173 in physicalcontact with the impeller windings 168, 169 respectively and wiring itinto a conventional voltage divider 174. Temperature changes areexperienced concurrently by the impeller windings and the temperaturesensitive elements 172, 173. This circuit provides a sufficient voltageregulation to maintain an approximately constant impeller flux over theexpected temperature range, the flux being sufficiently constant for thepurposes for which it is used.

Fourth Embodiment (FIG. 6)

The use of an electronic or photoelectric sensing system as describedabove for sensing the properties of a moving coin provides an immediatedetermination of the acceptability of a coin. Furthermore, also asdescribed above, it is a simple matter to reverse the direction ofmagnetic field travel produced by the impeller. In this fourthembodiment, illustrated in FIG. 6, the sensors 132, 133 are locatedwithin the magnetic field region, for example, within the pole pieces orbetween adjacent coils intermediate the ends of an impeller 200. Severalopportunities to utilize the impeller for additional functions areprovided by the capability for reversing the direction of a coin driveat a suitable moment during the coin's travel past the impeller 200 anddetermining the acceptability as well as the denomination of acceptablecoins at an instant when the coin remains under the influence of theimpeller. For example, the length of coin travel can be reduced bydecelerating the coin through reversal of magnetic field directionimmediately after determination of the coin's authenticity anddenomination. A substantial spacial separation of differing coins alsocan be achieved by selected use of coin deceleration or accelerationdependent upon the results of the determination of the coin'sauthenticity and denomination. In this manner, all rejected coins can bedirected to a rejection chute while acceptable coins can be individuallydirected to an appropriate receptacle for the coin's particulardenomination.

One construction for conserving space which can be utilized isschematically illustrated in FIG. 6 where a wall 202 is spaceddownstream from an impeller 200 and coin support track 203 a distanceslightly greater than the diameter of the largest coin which can beadmitted to the coin selector. After the coin leaves the impeller 200,the coin abuts the wall 202 and tends to rebound toward the impeller200; however, gravity prevents the coin from returning to the cointrack. The coin therefore drops downwardly between the impeller 200 andthe wall 202 toward a solenoid controlled inclined platform 204. If thecoin is determined to be acceptable by logic circuitry of the typeillustrated in FIG. 4, a control solenoid (not shown) is actuated toretract the platform 204 from the path of the coin allowing the coin tofall into an acceptance chute 206. If the coin is not acceptable, eitherbecause it is not authentic or because it is of an improperdenomination, the control solenoid is not actuated and the coin strikesthe platform 204 and bounces into a rejection chute 208. The amount ofspace required for this coin sensing device is minimized by eliminationof the space normally alloted to accommodate the coin's trajectories.

Impeller Series (FIG. 7-9)

Some of the advantages of placing the sensors within the impeller regionas described above can be achieved by using a second impeller locateddownstream from the sensors. Turning now to FIG. 7, there isschematically illustrated a coin selection system 220 having a primaryimpeller 222 which, as described earlier with reference to FIGS. 3 and4, accelerates electrically conductive coins. The velocity and chordaldimension of the coin are examined by the sensors, shown as a unit 218,located immediately after the impeller 222 and the determination of coinacceptability and denomination is made by a combinatorial circuit asdescribed earlier. A secondary impeller 226 is located immediately afterthe sensor unit 218 and, depending upon the determination already madeof the coin's acceptability and denomination, the secondary impellereither decelerates or accelerates the coin at a predetermined magnitudeso that the coin may be propelled into a proper chute such as chute 227for rejected coins, chute 228 for nickels or chute 229 for dimes.

An alternative to this latest embodiment is illustrated in FIG. 8wherein the primary impeller 222 additionally serves as a secondaryimpeller. After the coin is accelerated by the impeller 222 and passesthe sensor unit 218, it rolls up a curved inclined portion of the coinsupport track 230 and eventually is returned by gravity toward thesensor unit 218 and the impeller 222. During the first pass of the coinby the sensor unit 218, the sensor unit, with associated logic circuitrysuch as shown in FIG. 4, compares the coin's velocity and chordaldimension with respective properties of acceptable coins so that by thetime the coin returns, the coin analysis is complete. Depending upon theresults of the examinations of the velocity and chordal dimension of thecoin, during the return pass of the coin by the impeller 222, itaccelerates the coin at different rates. This system sorts acceptablecoins from the unacceptable coins and also separates the acceptablecoins by denomination. Because the initial portion of the track 230 alsoserves as the exit a removable wall or stop 232 is provided. As a coinenters the system, it is forced to rest against the stop 232 by theimpeller 222. The field direction of the impeller is then reversed andthe coin is impelled toward the sensor unit 218. A solenoid (not shown)retracts the stop 232 out of the coin passageway to permit the coin tomove off the track into the appropriate chute 227, 228 or 229. The stop232 returns to its initial position after a predetermined time interval.

It is possible to reduce the number of sensors required and simplify thelogic circuitry needed to perform coin discrimination by the use of aplurality of small impellers and coin support tracks. Such a system isillustrated in FIG. 9 wherein three inclined coin tracks 270, 272, 274and three corresponding impellers 276, 278, 280 are employed. The tracksand impellers are located such that a set of one track 272 and oneimpeller 278 is immediately below the lower end of the first impeller276 and track 270 and the third impeller 280 and track 274 are locatedbelow the higher end of the first impeller 276 and track 270. The slopeof each of the tracks depends upon the particular coin set with whichthe system is intended to be used. Three solenoid control stops 282,284, 286 and three arrival sensors 288, 290, 292 are provided, one stopand one arrival sensor for each of the impellers 276, 278, 280.

A coin introduced to the system through an entrance slot 294 passesthrough a meander path 296 and by an arrival sensor 288 and eventuallyfalls onto the first track 270 where it rests against a stop 282. Sincethe track 270 is inclined, the coin will roll toward the stop 282 andcome to rest and there is no need for the impeller to move the cointoward the stop 282. After a predetermined period of time sufficient toallow all coins to come to rest the impeller 276 is energized asdescribed above and, concurrently, the solenoid controlled stop 282 isremoved from the path of the coin to prevent interference with themovement of the coin. The coin, depending upon its diameter, acceptanceratio and weight either will roll down the track 270 falling off thelower end thereof or roll up the track 270 falling off the upper endthereof. In this manner, the first track 270 has performed an initialsorting function.

A coin which rolls off the lower end of the support track 270 passes thecoin presence sensor 290 and falls onto the second coin track 272 whereit comes to rest against the solenoid controlled stop 284. Aftersufficient time has elapsed the impeller 278 is energized and the stop284 is removed by a solenoid (not shown) and a secondary discriminationis performed. Those coins which can be impelled up the track 272 by theimpeller 278 roll off the upper end of the track in a spacial patterndependent upon the coin's acceptance ratio, weight and diameter and arecollected in the chutes 294. Similarly, those coins which cannot beimpelled up the track 272 will roll off the lower end of the track in aspacial pattern similarly representative of their acceptance ratio,weight and diameter and are collected in chute 295. A similardiscrimination is performed by the third roll track 274 and impeller280. In this fashion, at least four separations are available, namely,at the upper and lower ends of the tracks 272 and 274. Because of thespacial separation pattern which coins take due to the differentvelocities attained while on the tracks, a greater number ofdiscriminations are available. FIG. 9 illustrates two chutes 294 at theupper end of each of the tracks 272, 274 and two chutes 295 at the lowerend of these tracks for receiving eight categories of coins.

A particularly appropriate application for a coin sensor utilizing thisstructure is as a denominational sorter of legitimate coins for use bycoin collector entities such as vending companies, banks, supermarkets,etc., where the incidence of counterfeit and totally unacceptable coinsis low because the coins are given an initial visual or coin sensorscreening. A typical user would be the operator of some of the manyvending machines which have a coin sensor which does not separate theacceptable coins by denomination, but merely places them in a commoncollection receptacle.

If desired, coin presence sensors such as photocells 296 may be locatedat the entrance to each of the coin chutes 294, 295 which receive thecoins leaving the impellers with the output of the sensors beingdirected to a totalizer for calculating and recording the value of coinssorted.

Inclined Impeller (FIGS. 10 and 11)

It has been found that often coins of two different denominations havingthe similar composition and only marginally differing diameters areaccelerated to similar velocities by an impeller aligned parallel to thesupport track. In order to induce a greater velocity separation betweensuch coins of different denominations, an impeller 300 having a taperedpole structure may be used. As can be seen in FIG. 10, the height of theimpeller is varied from a dimension approximately equal to the diameterof the smallest acceptable coin 302 at one end 304 of the impeller to adimension approximately equal to the diameter of the largest acceptablecoin 306 at the other end 308 of the impeller. The smaller coinexperiences an almost uniform flux throughout the length of the impeller300 while the larger coin experiences a flux whose magnitude is afunction of position along the impeller.

In addition to the variation in flux magnitude experienced by coins ofdifferent sizes, the location of the flux relative to the coin supporttrack 310 also varies and plays an important part in the acceleration ofthe coins. The point about which the coins rotate as they roll down thetrack is the point of contact of the coin with the track. Given equalforces on the coin tending to make it rotate, the higher the force islocated on the coin with respect to the track the more effective theforce will be since the moment arm about the point of rotation will begreater. Looking at the coins at the beginning of the track 310 in FIG.10, it can be seen that the forces on the small coin 302 are exertedover the entire height of the coin whereas the forces exerted on thelarger coin 306 are exerted on the lower half of the coin. Because ofthe moment of inertia of a coin is a function of its diameter andbecause the coin acceleration is a function of the distance from theapplication of the moving force to the point of rotation of the coin, itcan be seen that the acceleration of the coins will vary significantlydepending upon the coin's diameter and the slope of the tapered impeller300. As with the previous embodiments, after the coin leaves theimpeller 300 its chordal dimension and velocity are examined by a sensorarray 309 and associated combinatorial circuitry.

A similar result can be achieved by using a rectangular inclinedimpeller 312 as illustrated in FIG. 11. It can be seen that the smallercoins can be exposed completely to the magnetic field at the beginningof the coin support track 314 while only a small lower portion of thelarger coin 306 is exposed to the magnetic field at the beginning of thecoin track. As the coins progress down the track, a smaller percentageof the small coin 302 is exposed to the magnetic field while the pointof application of the magnetic field on the larger coin 306 risesproviding a larger torque and resulting in increased acceleration of thelarger coin. Since the acceleration of coins of different sizes vary asthe coin proceeds down the track 314 it is desirable to sense coinacceleration between two points along the path of coin travel. This isaccomplished by locating two spaced apart photocells 316, 318 so thatthe coins pass the photocells while they are under the influence of theimpeller 312. By using circuitry of the type described above withrespect to FIG. 4, the time interval which the coin moves from the firstphotocell 316 to the second photocell 318 is recorded by a counter and,through the use of comparative circuitry, such as flip flops, adetermination is made concerning the authenticity and denomination ofthe impelled coin.

I claim:
 1. A device for determining the denomination of a coincomprising a coin passageway .Iadd.including a track for supporting acoin on its edge, .Iaddend.means for admitting a coin to the passageway,an impeller of electrically conductive coins adjacent to the.[.passageway.]. .Iadd.coin support track, .Iaddend.the impellercomprising means for generating a magnetic field traveling relative to acoin .[.in the passageway.]. .Iadd.on the coin support track,.Iaddend.the generated magnetic field inducing eddy currents in the coinand interacting with the magnetic fields associated with the inducededdy currents to impel the coin .Iadd.along the coin support track.Iaddend.in the direction of the traveling magnetic field, and means forexamining a velocity related property of the coin .Iadd.while the coinis still supported by the track and .Iaddend.after the coin has beenexposed to at least a portion of the generated magnetic field.
 2. Adevice for comparing characteristics of a coin with characteristics of agenuine coin of given denomination comprising a passageway forconducting the coin along a predetermined path, a magnetic fieldgenerator so positioned in proximity to the passageway that a coin inthe passageway may be brought within its field, means associated withthe generator to apply to a coin in the field a force having a componentaligned with the path by moving the field relative to the passageway,and means for comparing .[.a characteristic representative of thevelocity of.]. .Iadd.the time for .Iaddend.the coin which has been actedupon by the field .Iadd.to travel a known distance .Iaddend.with thecorresponding .[.characteristic of.]. .Iadd.time for .Iaddend.a genuinecoin of the given denomination.
 3. A method of determining thedenomination of a .Iadd.non-ferromagnetic electrically conductive.Iaddend.coin comprising the steps of generating a traveling magneticfield, directing a coin to .Iadd.a coin support track in .Iaddend.themagnetic field so that the field impels the coin in a desired direction.Iadd.along the coin support track, .Iaddend.and examining a velocityrelated characteristic of the coin when the coin has been impelled.Iadd.along the coin support track and while it is still supported bythe track.Iaddend. .
 4. A method as defined in claim 3 wherein thetraveling magnetic field is generated by moving a plurality of magnetsrelative to the coin in the direction in which it is desired to impelthe coin.
 5. A method as defined in claim 3 including the step ofarresting the movement of the coin .[.as.]. .Iadd.along the coin supporttrack immediately before .Iaddend.the coin .[.approaches.]. .Iadd.issubjected to .Iaddend.the traveling magnetic field.
 6. A method asdefined in claim 3 including the steps of arresting movement of a coinby impelling the coin in a first direction .Iadd.along the coin supporttrack .Iaddend.causing the coin to abut a stationary member and thenimpelling the coin in a second direction .Iadd.along the coin supporttrack .Iaddend.opposite to the first direction.
 7. A method as definedin claim 3 wherein the .[.impeller.]. .Iadd.traveling magnetic field.Iaddend.is .Iadd.generated by an .Iaddend.electrically operated.Iadd.impeller .Iaddend.and including the step of sensing the impellercoil temperature and regulating the impeller supply voltage as afunction of the impeller coil temperature.
 8. A method as defined inclaim 3 wherein the velocity related property is examined while the coinis under the magnetic influence of the traveling magnetic field andincluding the step of varying the magnitude of the magnetic field by anamount based upon a predetermined .[.program.]. .Iadd.function.Iaddend.related to the denomination of the coin.
 9. A method as definedin claim 3 wherein .Iadd.the coin support track along which .Iaddend.thecoin is impelled .[.along.]. .Iadd.is .Iaddend.an inclined track.
 10. Amethod as defined in claim 3 including the steps of examining a chordaldimension of the coin, examining the velocity related characteristicwhile the coin is under the influence of the traveling magnetic fieldand comparing the coin's chordal dimension and velocity relatedcharacteristic with predetermined values to determine the denominationof the coin.
 11. A method as defined in claim 10 including the step ofvarying the magnitude of the magnetic field by an amount based upon apredetermined .[.program.]. .Iadd.function .Iaddend.related to thedenomination of the coin.
 12. A method as defined in claim 3 wherein thetraveling magnetic field is generated by supplying a variable current toa plurality of longitudinally spaced coils such that the current throughadjacent coils has a phase shift relationship.
 13. A method as definedin claim 12 wherein the .[.impeller is.]. .Iadd.coils comprise an.Iaddend.electrically operated .Iadd.impeller .Iaddend.and including thesteps of sensing the current supplied to the impeller, producing asignal dependent upon a velocity related characteristic of a coin,comparing that signal with predetermined signals characteristic ofacceptable coins, and accounting for variations in the current from apredetermined standard during the comparison step.
 14. A method asdefined in claim 12 including the steps of arresting the movement of thecoin in said direction .Iadd.along the coin support track,.Iaddend.sensing the arrival of a coin .Iadd.on the coin support track.Iaddend.and supplying the variable current to the coils in response toa signal from the coin sensor.
 15. A method as defined in claim 14including the steps of causing the coin to move in a first direction.Iadd.along the coin support track .Iaddend.and abut against astationary member and then impelling the coin in a second direction.Iadd.along the coin support track .Iaddend.opposite to the firstdirection.
 16. A device for determining the authenticity of a.Iadd.non-ferromagnetic electrically conductive .Iaddend.coin comprisinga coin passageway .[.having.]. .Iadd.including .Iaddend.an entrance forthe reception of a coin .Iadd.and a coin support track for supporting acoin on its edge, .Iaddend.a coin accelerating impeller adjacent to the.[.passageway.]. .Iadd.coin support track, .Iaddend.the impellercomprising means for generating a magnetic field having a componenttraveling along a region of the .[.passageway.]. .Iadd.coin supporttrack, .Iaddend.the magnetic field component being arranged to impel acoin along the .[.passageway.]. .Iadd.coin support track, .Iaddend.andmeans for examining a function dependent upon the velocity of the coin.Iadd.while it is still supported by the track and .Iaddend.after thecoin has passed .Iadd.along the coin support track .Iaddend.through atleast a portion of the region.
 17. The device of claim 16 wherein the.[.coin passageway includes a.]. a coin support track .[.having.]..Iadd.has .Iaddend.a slope greater than 0° and less than 5° to thehorizontal.
 18. The device of claim 16 including coin arrival sensingmeans for sensing the arrival of a coin in the device and means actuatedby the arrival sensing means for actuating the impeller.
 19. The deviceof claim 16 including means for reversing the direction in which themagnetic field travels.
 20. The device of claim 16 including .[.a coinsupport across the passageway onto which a coin entering the devicedrops and.]. a coin stop adjacent to the coin support .Iadd.track,.Iaddend.means for initially directing .[.the.]. .Iadd.a coin.Iaddend.entering .[.coin.]. .Iadd.the device .Iaddend.toward the coinstop .[.and means to impel.]. .Iadd.wherein the impeller impels.Iaddend.the coin away from a position of rest against the coin stoptoward the velocity dependent function examining means.
 21. A device asdefined in claim 16 wherein the impeller is electrically operated andincluding means for regulating the impeller supply voltage as a functionof the impeller temperature so that the impeller provides a relativelyconstant magnetic flux as the impeller temperature varies.
 22. Thedevice of claim 16 wherein the velocity dependent function examiningmeans provides an output signal related to the velocity of the coinwhile the coin is under the magnetic influence of the impeller, firstcircuit means for comparing the output signal with predetermined signalscharacteristic of acceptable coins and for providing a resultant signalindicative of the coin's denomination, means .[.sensitive.]..Iadd.responsive .Iaddend.to the resultant signal to modify thetraveling magnetic field in order to spacially separate the coins inaccordance with their velocity dependent function.
 23. The device ofclaim 16 .[.wherein the coin passageway includes a coin support trackadjacent to the impeller and.]. wherein the impeller provides a magneticfield region across the passageway which varies in location height abovethe coin support track along at least a portion of the length of thecoin support track.
 24. The device of claim 16 including means providinga first signal dependent upon the chordal dimension of the coin andwherein the velocity dependent function examining means provides asecond signal related to the velocity of the coin as the coin passessaid examining means and means for comparing the first and secondsignals with predetermined signals characteristic of acceptable coins.25. The device of claim 16 wherein the impeller comprises at least onemagnet having a component of motion in the direction in which it isdesired to impel the coin.
 26. The device of claim 25 .[.wherein thecoin passageway includes a coin support track and.]. wherein the magnetis arranged for rotation about an axis positioned with relation to thepassageway as to dispose in proximity to the support track a magneticfield having a major component in the desired direction of coin travelalong the support track.
 27. A device as defined in claim 16 wherein theimpeller is electrically operated and wherein the velocity dependentfunction examining means provides an output signal dependent upon thevelocity of the coin as the coin passes the examining means andincluding a first circuit means for comparing the output signal withpredetermined signals characteristic of acceptable coins, means.[.sensitive.]. .Iadd.responsive .Iaddend.to the impeller current andoperatively connected to the first circuit means to modify the operationof the first circuit means to compensate for variations in the impellercurrent.
 28. A device as defined in claim 27 wherein the examining meansincludes a pair of coin presence sensors and wherein the first circuitmeans includes a pulsating signal source, a pulse counter, and gatemeans for gating the pulsating signal to the counter in response to.Iadd.a .Iaddend.signal from the coin presence sensors, and wherein thepulsating signal source frequency is controlled by the impeller currentsensitive means.
 29. The device of claim 16 wherein .[.the coinpassageway includes a first coin support track adjacent to the coinaccelerating impeller, said.]. .Iadd.the coin support .Iaddend.track.[.sloping.]. .Iadd.slopes .Iaddend.upwardly in the direction in whichthe magnetic field travels.
 30. The device of claim 29 .[.including.]..Iadd.wherein the coin passageway includes .Iaddend.a second coinsupport track and a second impeller adjacent to the second coin supporttrack, the second coin support track and second impeller being locatedbelow one end of the .[.first.]. coin support track whereby coinsleaving said one end of the .[.first.]. coin support track drop onto thesecond coin support track adjacent to the second impeller.
 31. Thedevice of claim 16 including means for arresting movement of the coin.Iadd.along the coin support track immediately .Iaddend.before theimpeller impels the coin toward the velocity dependent functionexamining means.
 32. The device of claim 31 wherein the movementarresting means includes .[.a coin support across the passageway ontowhich the coin is directed, the coin support having.]. an initialsection .Iadd.of the coin support track .Iaddend.inclining from one endthereof and a second section declining from the other end of the firstsection, a coin stop adjacent to said one end and means for directing acoin entering the device toward the initial section whereby the coinrests against the coin support .Iadd.track .Iaddend.and coin stop. 33.The device of claim 32 wherein the inclining and declining sections areeach at an angle of between 0.5° and 5° from horizontal.
 34. The deviceof claim 16 wherein the velocity dependent function examining meansprovides an output signal related to the velocity of the coin, firstcircuit means for comparing the output signal with predetermined signalscharacteristic of acceptable coins and for providing a resultant signalindicative of the coin's denomination, means .[.sensitive.]..Iadd.responsive .Iaddend.to the resultant signal to modify the velocityof the coin in order to spacially separate the coin from other coinsexamined in accordance with the differences in their velocity dependentfunctions.
 35. The device of claim 34 wherein the means .[.sensitive.]..Iadd.responsive .Iaddend.to the resultant signal are arranged tofurther impel the coin an amount dependent upon the coin's denomination.36. The device of claim 35 wherein the means .[.sensitive.]..Iadd.responsive .Iaddend.to the resultant signal is arranged to impelthe coin in a direction different from the coin's direction when thecoin is exposed to the velocity dependent function examining means. 37.The device of claim 16 wherein the impeller comprises a plurality ofcoils spaced in the desired direction of coin travel and an electricalpower source for supplying a variable current to the coils in a mannersuch that a phase shift relationship exists between adjacent coilsproviding a magnetic field traveling in one direction.
 38. The device ofclaim 37 including means for actuating the impeller at a predeterminedpoint in the wave form of the variable current.
 39. The device of claim37 wherein each of the coils are wound around a pole piece and arelocated on one side of the coin passageway and including magnetic shuntmeans on the side of the passageway opposite the coils.
 40. The deviceof claim 39 wherein the dimensions between two adjacent pole pieces isno greater than the diameter of the smallest coin which the device isdesigned to accept.